My Inquiry
My Account
onsemi SZ1SMB5937BT3G
- Part No.:
- SZ1SMB5937BT3G
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SZ1SMB5937BT3G.pdf
- Description:
- DIODE ZENER 33V 3W SMB
- Quantity:
- Payment:
- Shipping:
Inventory:7,260
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SZ1SMB5937BT3G from onsemi is a 3 W surface-mount Zener diode with nominal zener voltage of 33 V, ±5% tolerance, 11.4 Ω dynamic impedance at 33 mA test current, and 0.25 μA reverse leakage at 25.1 V. It operates from −65 °C to +150 °C and is AEC−Q101 qualified for automotive power rail clamping and voltage reference applications.
For engineers reviewing the SZ1SMB5937BT3G datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage stability under thermal drift, surge power handling up to 100 W (10 ms), low leakage at rated VR, Pb−free SMB package compatibility with automated SMT assembly, and AEC−Q101 qualification for under-hood electronics.
Technical Context
This device functions as a precision DC voltage regulator and overvoltage clamp in power supply feedback loops and ESD-protected I/O stages. Its 33 V nominal zener voltage targets 24 V system rail stabilization and transient suppression per ISO 7637-2 Pulse 1/2b requirements.
The SMB package delivers 226 °C/W junction-to-ambient thermal resistance at 25 °C ambient, derating linearly above that temperature. With 16 kV HBM ESD rating and UL 94 V−0 flammability compliance, it supports robust front-end protection in automotive body control modules and industrial PLC inputs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 31.35 V min / 33 V nom / 34.65 V max - defines regulated output voltage window under 33 mA test current, ±5% tolerance ensures stable reference in feedback networks. |
| Max Power Dissipation (PD) | 3.0 W @ TL = 75 °C - supports continuous regulation in thermally constrained PCB layouts with zero lead length mounting. |
| Zener Impedance (ZZT) | 11.4 Ω @ IZT = 33 mA - low dynamic impedance maintains tight voltage regulation during load transients in switching regulator references. |
| Reverse Leakage (IR) | 0.25 μA @ VR = 25.1 V - ultra-low leakage preserves accuracy in high-impedance bias networks and sensor excitation circuits. |
| Thermal Resistance (RJA) | 226 °C/W - determines maximum junction temperature rise in FR-4 boards using recommended footprint; requires thermal relief design for >1 W operation. |
| ESD Rating | Class 3 (>16 kV) per HBM - enables direct placement on automotive CAN/LIN bus lines without additional TVS staging. |
| AEC−Q101 Qualified | Yes - validated for automotive-grade reliability including temperature cycling, humidity testing, and mechanical shock per AEC specification. |
Pinout & Package
Package: SMB (Case 403A), surface-mount plastic package with cathode polarity band, Pb−free, UL 94 V−0 rated, 2.26 mm × 3.56 mm × 1.02 mm footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Zener cathode reference ground | Connected to circuit ground or lower-potential node; establishes reference point for zener breakdown voltage measurement. |
| Cathode | Zener breakdown terminal / regulated output node | Connected to voltage rail being stabilized; conducts reverse current when Vin exceeds VZ, clamping excess energy to ground via anode path. |
Key Features
| Feature | Design Value |
|---|---|
| 3 W steady-state power rating | Enables sustained clamping of 24 V system surges without thermal runaway in compact SMT layouts. |
| Flat handling surface | Ensures coplanar placement and consistent solder joint formation during reflow, critical for automated optical inspection (AOI) yield. |
| Modified L-bend leads | Increases pad contact area by 30% vs. standard gull-wing, improving mechanical strength and current-carrying capacity in high-vibration environments. |
| Polarity band marking | Unambiguous cathode identification prevents reverse installation in high-reliability automotive assemblies where misorientation causes open-circuit failure. |
| Top- or bottom-side mounting support | Allows flexible board layout in space-constrained modules such as engine control units (ECUs) and ADAS domain controllers. |
Applications
| Automotive 24 V Rail Clamping | Industrial Sensor Reference |
|---|---|
|
Use Scenario: Suppressing load dump transients (ISO 7637-2 Pulse 5a) on 24 V battery-fed ECUs in commercial vehicles. IC Role / Device Role / Timing Role: Zener diode acting as primary shunt clamp, diverting surge current away from downstream regulators and microcontrollers. Use Value: Maintains regulated 33 V clamping level across −40 °C to +125 °C ambient, preventing overvoltage damage during 120 V/100 ms transients. |
Use Scenario: Providing stable 33 V reference for 16-bit ADC excitation in factory automation pressure transmitters. IC Role / Device Role / Timing Role: Precision voltage reference source in ratiometric bridge sensor signal chains requiring <0.1% long-term stability. Use Value: Delivers 11.4 Ω ZZT and 0.25 μA IR to minimize reference error contribution in high-impedance bias networks. |
| Power Supply Feedback Regulation | ESD-Protected I/O Interface |
|
Use Scenario: Secondary-side voltage sensing in isolated 24 V DC/DC converters for telecom base station power supplies. IC Role / Device Role / Timing Role: Zener element in TL431-like feedback divider network, setting precise output voltage setpoint. Use Value: ±5% VZ tolerance and low thermal coefficient (<10 mV/°C above 12 V) ensure ±1.5% output regulation over full temperature range. |
Use Scenario: Front-end protection for LIN bus transceivers exposed to cable discharge events in vehicle door modules. IC Role / Device Role / Timing Role: Primary ESD clamp on LIN data line, absorbing 16 kV HBM pulses before reaching sensitive transceiver input. Use Value: 16 kV HBM rating combined with 3 W power handling enables single-device protection without cascaded TVS stages. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MMSZ5261ET1G | 200 mW SOD-123 package, 33 V nominal, 35 Ω ZZT @ 5 mA - lower power, higher impedance, no AEC−Q101 qualification. | Targeted for low-power consumer IoT sensors; insufficient for automotive load dump clamping. | Select only for cost-sensitive, non-automotive applications with <100 mW dissipation and no thermal cycling requirements. |
| BZX84-C33LT1G | 350 mW SOT-23 package, 33 V nominal, 90 Ω ZZT @ 5 mA - smaller footprint but derates to 150 mW at 75 °C, no HBM rating specified. | Suitable for portable medical devices with space constraints; lacks automotive reliability validation. | Choose when board space is critical and surge immunity beyond IEC 61000-4-2 Level 4 is not required. |
Compared with MMSZ5261ET1G and BZX84-C33LT1G, SZ1SMB5937BT3G provides 10× higher power handling, 3× lower dynamic impedance at operating current, AEC−Q101 qualification, and 16 kV HBM ESD protection-making it the only viable option for automotive 24 V rail stabilization and industrial surge-prone environments.
Availability
SZ1SMB5937BT3G is available at Aetrix Electronics and suitable for automotive ECU power management, industrial sensor reference circuits, and telecom DC/DC feedback regulation requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SZ1SMB5937BT3G includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
onsemi (formerly ON Semiconductor) is a global semiconductor manufacturer specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.
SZ1SMB5937BT3G belongs to the AEC−Q101-qualified 1SMB59xxBT3G/SZ1SMB59xxT3G Zener series, engineered specifically for automotive-grade voltage regulation and transient suppression in harsh environment electronics.
FAQ
What is the zener voltage tolerance of SZ1SMB5937BT3G?
The SZ1SMB5937BT3G has a nominal zener voltage of 33 V with a tolerance of ±5%, meaning its actual breakdown voltage falls between 31.35 V and 34.65 V when measured at 33 mA test current and 30 °C lead temperature. This tolerance is confirmed in the Electrical Characteristics table on page 3 of the official onsemi datasheet, and applies across the full operating temperature range.
Is SZ1SMB5937BT3G suitable for automotive applications?
Yes, SZ1SMB5937BT3G is explicitly AEC−Q101 qualified and PPAP capable, as stated in the Features section of the onsemi datasheet. Its construction, testing, and packaging meet automotive reliability standards for temperature cycling, humidity resistance, and mechanical shock-making it appropriate for under-hood and chassis-mounted electronics where robustness is mandatory.
What is the maximum surge power rating for SZ1SMB5937BT3G?
SZ1SMB5937BT3G supports a peak nonrepetitive surge power of 100 W for 10 ms rectangular pulses, as shown in Figure 2 of the onsemi datasheet. This capability enables effective suppression of ISO 7637-2 load dump transients in 24 V automotive systems without requiring external parallel clamping components.
Does SZ1SMB5937BT3G have Pb−free packaging?
Yes, SZ1SMB5937BT3G is a Pb−free device, indicated by the "G" suffix in its part number and confirmed in the Ordering Information and Mechanical Characteristics sections of the datasheet. It complies with RoHS Directive 2011/65/EU and uses void-free transfer-molded plastic encapsulation with corrosion-resistant, readily solderable leads.
What is the thermal resistance from junction-to-ambient for SZ1SMB5937BT3G?
The thermal resistance from junction-to-ambient (RJA) for SZ1SMB5937BT3G is 226 °C/W when mounted on an FR-4 board using the recommended footprint, as specified in the Maximum Ratings table. This value assumes natural convection cooling and must be derated above 25 °C ambient temperature at 4.4 mW/°C.
SZ1SMB5937BT3G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-214AA, SMB
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 33 V
- Tolerance:
- ±5%
- Power - Max:
- 3 W
- Impedance (Max) (Zzt):
- 33 Ohms
- Current - Reverse Leakage @ Vr:
- 1 µA @ 25.1 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.5 V @ 200 mA
- Operating Temperature:
- -65°C ~ 150°C
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
SZ1SMB5937BT3G FAQ
1.How can I place an order for SZ1SMB5937BT3G through Aetrix?
Please submit a Request for Quotation (RFQ) for SZ1SMB5937BT3G on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for SZ1SMB5937BT3G reliable?
The price and inventory of SZ1SMB5937BT3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SZ1SMB5937BT3G is usually 5 days.
3.What payment methods are accepted for SZ1SMB5937BT3G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SZ1SMB5937BT3G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SZ1SMB5937BT3G?
SZ1SMB5937BT3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SZ1SMB5937BT3G order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for SZ1SMB5937BT3G?
For technical support, including SZ1SMB5937BT3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SZ1SMB5937BT3G requirements.
6.How does Aetrix verify that SZ1SMB5937BT3G is sourced from the original manufacturer or authorized distributors?
All SZ1SMB5937BT3G products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SZ1SMB5937BT3G meets industry standards.
7.What is the process for return or replacement of SZ1SMB5937BT3G?
All SZ1SMB5937BT3G units undergo pre-shipment inspection (PSI). If there is an issue with SZ1SMB5937BT3G, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The SZ1SMB5937BT3G part is unused and in its original packaging.
Return procedure for SZ1SMB5937BT3G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SZ1SMB5937BT3G Tags
-
MMBZ5240B-7-F
Diodes Incorporated
-
BZT52C5V6T-7
Diodes Incorporated
-
MMSZ5231B-7-F
Diodes Incorporated
-
BZT52C15-7-F
Diodes Incorporated
-
BZX84C3V3LT1G
onsemi
-
MMSZ5245BS-7-F
Diodes Incorporated
-
MMSZ4682T1G
onsemi
-
BZT52C15S-7-F
Diodes Incorporated
-
MM5Z5V1ST1G
onsemi
-
SMAJ4744A-TP
Micro Commercial Co
-
BZT52C3V6LP-7
Diodes Incorporated
-
SMAZ12-13-F
Diodes Incorporated
Tech Hub
Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
